1. Field
The present invention relates to a synchronization control apparatus, an information processing apparatus, and a synchronization management method.
2. Description of the Related Art
In a current large-scale and mission-critical server system, it is known that a hardware configuration is made redundant so that the whole of the system is not stopped due to a hardware fault or the like. For this reason, regarding a CPU (Central Processing Unit) too, a redundant CPU technology has been developed in which a plurality of CPU's of the same configuration are embedded in the system in advance. Two CPU's are always caused to implement the same process simultaneously, and a result of the process from an optional CPU is output to the exterior. In the event that either CPU goes wrong, the wrong CPU is separated from the system, while the one remaining normal CPU is caused to continue the process, and a result of the process from the normal CPU is output to the exterior.
Naturally, there may be a case in which only a process executed by one CPU is delayed or hangs due not to a hardware fault but to a software error, thereby causing a synchronization delay between the plurality of CPU's. In such a case, there may be a case in which it is possible, depending on a degree of the error, to restore a condition in which the two CPU's are synchronized with each other (that is, a redundant configuration) by once stopping a CPU in which an abnormality has occurred, and reproducing (initializing) internal information of a normal CPU in the former.
Therefore, there is a need for a synchronization control apparatus which monitors an existence or otherwise of a synchronization delay between the two CPU's, and executes and retries a resynchronization process which, in the event that a synchronization delay has occurred, resynchronizes a CPU in which a failure has occurred by resetting and initializing it.    [Patent Document 1] Japanese Laid-open Patent Application No. 2006-302289    [Patent Document 2] Japanese Laid-open Patent Application No. 2005-285119